Various parts of the coffee tree have been used for nutritional purposes for a relatively long time (see e.g., Pendergrast, M. Uncommon Grounds. Basic Books: New York, 1999). For example, coffee tree leaves and fresh, ripe coffee cherries were boiled to make tea. In other examples, the pulp of the coffee cherry can be fermented to produce wine as described in Chinese Patent CN 1021949. Alternatively, as described by Bustamante (see e.g., U.S. Pat. No. 4,165,752, GB 2026839, and CA 1104410) coffee cherries were compressed, dehydrated, comminuted, and roasted to manufacture a smokable coffee product. A schematic illustration of a coffee cherry is depicted in Prior Art FIG. 1.
In still further well known uses, the seeds (i.e., the beans) of the coffee tree are isolated from the cherry, dried, roasted, ground, and extracted with hot water to provide the beverage that many users enjoy as coffee. Isolation of the coffee beans (“coffee processing”) will typically vary depending on the location of the coffee plant, and may be categorized as wet processing or dry processing.
Wet processing is typically employed in relatively humid growing regions at relatively high elevations (e.g., Hawaii, Mexico, Jamaica) and is generally considered to produce higher quality coffees. In contrast, dry processing is normally used in sunny, lower rain regions (e.g., Brazil, Africa, Indonesia) and is considered to produce lower quality coffees, but is simpler and often requires less equipment. Variations of these processes are often used, but will typically fall into the basic classes of wet or dry processing described in the subsequent paragraphs.
In a traditional wet processing method as exemplified in Prior Art FIG. 2A, the pulp is removed from the ripe coffee cherry to give coffee cherry pulp plus mucilage-coated parchment (hull-covered green beans). The mucilage-coated parchment is then fermented in a tank of water, whereby the mucilage loosens from the parchment, and the mucilage-containing water is then drained. The parchment is dried in the sun or with a mechanical dryer, and after drying to a specified moisture level, the parchment is passed through a huller that removes the hull from the green beans. Alternatively, mucilage removal may also be accomplished in a single step by use of a demucilaging pulper. In a final step, the green beans are sorted by size, and broken beans and off-color beans are removed. The sorted green beans are then bagged and stored for future sale or roasted. Thus, products, by-products, and waste products of the traditional wet processing method include coffee cherry pulp, mucilage-containing water, parchment, hull, broken and off-color green beans, and intact green beans. Traditionally parchment and intact green beans are the only materials retained for sale or storage, while all other derivatives are discarded, used as organic compost, or burned as fuel.
In a traditional dry processing method as exemplified in Prior Art FIG. 2B, ripe coffee cherries are picked and dried on concrete or soil pads. Alternatively, the ripe coffee cherries are dried on the tree and then picked (“natural-dry” method). The dried ripe coffee cherries are subsequently passed through a huller to remove the “husk” (dry combination of pulp, mucilage, and hull), and the green beans are sorted by size (broken beans and off-color beans removed), bagged, and stored for future sale or roasted. Thus, products, by-products, and waste products of the traditional dry processing method include “husk”, broken and off-color green beans, and intact green beans. Similar to the wet process, traditionally intact green beans are the only materials retained for sale or storage. The other derivatives are traditionally discarded, used as organic compost, or burned as fuel.
Regardless of the source (wet or dry processing), by-products and waste products are often problematic. For example, pulp and mucilage are relatively acidic, corrosive to equipment, and difficult to safely dispose (e.g., can lower the pH of waterways which could potentially be deleterious to fish and other water organisms (Mazzafera, 2002)). Furthermore, where the pulp is discarded in a landfill or other disposal site, rotting pulp will often generate significant odors over time.
Therefore, by-products and waste products have often been viewed as materials which are either unusable, hazardous, or of negligible value. However, each component of the whole coffee cherry possesses many potentially beneficial substances if preserved in a non-degraded (non-fermented) state. For example, fresh pulp contains high levels of polyphenol antioxidants, and fresh mucilage contains complex polysaccharides and antioxidants. The hull also contains small amounts of polyphenols (less than pulp or green coffee beans) and thus could be used as an additional source for antioxidants.
Unfortunately, coffee cherries, and especially the pulp and husk tend to rapidly spoil in the presence of molds, fungi, and other microorganisms, and therefore contain almost always significant levels of mycotoxins (see e.g., Pittet, A., Tornare, D., Huggett, A., Viani, R. Liquid Chromatographic Determination of Ochratoxin A in Pure and Adulterated Soluble Coffee Using an Immunoaffinity Column Cleanup Procedure. J. Agric. Food Chem. 1996, 44, 3564-3569; or Bucheli, P., Kanchanomai, C., Meyer I., Pittet, A. Development of Ochratoxin A during Robusta (Coffea canephora) Coffee Cherry Drying. J. Agric. Food Chem. 2000, 48, 1358-1362). Thus, products produced from the coffee pulp, husk, mucilage, and/or whole coffee cherry generally failed to find acceptance (Although one product is advertised as “coffee cherry tea” [http://www.paradiserelocation.com/paradisetogo/foodproducts.htm], the product is actually made from coffee cherry pulp and was recently determined to have substantial quantities of mycotoxins).
There are numerous methods known in the art to remove mycotoxins, and exemplary methods include extraction or absorption from a food product (U.S. Pat. No. 4,436,756 to Canella et al., or U.S. Pat. No. 5,935,623 to Alonso-Debolt). Alternatively mycotoxins may be degraded as described in U.S. Pat. No. 5,716,820 or U.S. Pat. No. 6,025,188 to Duvick et al. In still further known methods, pesticides or other compositions that control microbial growth or production of mycotoxins in microorganisms may be employed as described in U.S. Pat. No. 5,639,794 to Emerson et al., U.S. Pat. No. 4,199,606 to Bland, U.S. Pat. No. 5,698,599 to Subbiah, or U.S. Pat. No. 3,798,323 to Leary. However, all or almost all of the known methods add substantial cost to the detoxified product, and/or are often impracticable at the site where the coffee plants are located (e.g., lack of equipment or energy sources). Still further, many of the known methods tend to leave residual quantities of chemicals in the detoxified product, thereby decreasing the potential product value or increasing health concerns.
Thus, despite numerous beneficial properties of coffee cherries and its components, whole coffee cherries are generally not used as food products as mycotoxins are typically present in substantial quantities in the ripe and overripe fruit. Consequently, consumer friendly methods for use of coffee cherries in food products or for extraction of nutrients are generally not developed. Therefore, there is still a need to provide improved methods for coffee cherries, and especially for products comprising coffee cherries with low or no mycotoxin content for human and veterinary consumption.